The present invention relates to a method and an arrangement for cleaning the guide rollers of printing presses.
In conventional presses, the web of printing paper to be printed on passes from a feed roller, through the printing machine in which the paper is printed on one or both sides thereof, and thereafter, when printing is completed, over one or more guide rollers to a paper-folding mechanism where the printed paper web is cut and folded. The guide rollers are either freely rotating or motor-driven for rotation. Several tens of such rollers may be provided for guiding each paper web between the printing machine and the folding mechanism.
These guide rollers are dirtied successively with printing ink from the paper print. Consequently, it is necessary to remove these ink deposits regularly from the guide rollers, so as to prevent pleating or scrinkling of the paper web and the transfer of ink deposits onto the web. Various methods for cleaning such guide rollers manually are known in the art. For instance, subsequent to removing the paper web, the guide rollers can be scraped free of such deposits, either with or without the aid of a cleansing agent. This cleansing method is both laborious and highly time consuming, and also very expensive.
Several methods of removing printing ink from printing rollers mechanically are also known in the art. Examples of such methods are found in U.S. Pat. Nos. 4,058,059, 4,344,361 EP 0 257 818, SE 455 396, SE 417 298, U.S. Pat. No. 3,120,805 and U.S. Pat. No. 2,731,916. In principle, the methods taught by these publications involve applying a movable cleaning device to a dirty printing roller. Printing-ink solvent is transferred from the cleaning device to the printing roller, either by spraying or by brushing with the aid of brushes. The solubilized printing-ink is wiped from the roller with a cloth or with paper provided in rollform on the cleaning device, or is scraped-off with brushes or knives on the device. The described methods, however, are suitable only for cleaning printing rollers. A cleaning unit of the described kind is much too bulky and expensive for use in cleaning relatively small and relatively many guide rollers. Furthermore, in the majority of cases, the use of such a cleaning unit requires that the paper web be removed from the guide rollers.